Ext.ux.TreeCheckNodeUI = function() {
 //多选: 'multiple'(默认)
 //单选: 'single'
 //级联多选: 'cascade'(同时选父和子);'parentCascade'(选父);'childCascade'(选子)
 this.checkModel = 'multiple';
 
 //only leaf can checked
 this.onlyLeafCheckable = false;
 
 Ext.ux.TreeCheckNodeUI.superclass.constructor.apply(this, arguments);
};
Ext.extend(Ext.ux.TreeCheckNodeUI, Ext.tree.TreeNodeUI, {
    renderElements : function(n, a, targetNode, bulkRender){
     var tree = n.getOwnerTree();
  this.checkModel = tree.checkModel || this.checkModel;
  this.onlyLeafCheckable = tree.onlyLeafCheckable || false;
     
        // add some indent caching, this helps performance when rendering a large tree
        this.indentMarkup = n.parentNode ? n.parentNode.ui.getChildIndent() : '';
        //var cb = typeof a.checked == 'boolean';
  var cb = (!this.onlyLeafCheckable || a.leaf);
        var href = a.href ? a.href : Ext.isGecko ? "" : "#";
        var buf = ['<li class="x-tree-node"><div ext:tree-node-id="',n.id,'" class="x-tree-node-el x-tree-node-leaf x-unselectable ', a.cls,'" unselectable="on">',
            '<span class="x-tree-node-indent">',this.indentMarkup,"</span>",
            '<img src="', this.emptyIcon, '" class="x-tree-ec-icon x-tree-elbow" />',
            '<img src="', a.icon || this.emptyIcon, '" class="x-tree-node-icon',(a.icon ? " x-tree-node-inline-icon" : ""),(a.iconCls ? " "+a.iconCls : ""),'" unselectable="on" />',
            cb ? ('<input class="x-tree-node-cb" type="checkbox" ' + (a.checked ? 'checked="checked" />' : '/>')) : '',
            '<a hidefocus="on" class="x-tree-node-anchor" href="',href,'" tabIndex="1" ',
             a.hrefTarget ? ' target="'+a.hrefTarget+'"' : "", '><span unselectable="on">',n.text,"</span></a></div>",
            '<ul class="x-tree-node-ct" style="display:none;"></ul>',
            "</li>"].join('');
        var nel;
        if(bulkRender !== true && n.nextSibling && (nel = n.nextSibling.ui.getEl())){
            this.wrap = Ext.DomHelper.insertHtml("beforeBegin", nel, buf);
        }else{
            this.wrap = Ext.DomHelper.insertHtml("beforeEnd", targetNode, buf);
        }
       
        this.elNode = this.wrap.childNodes[0];
        this.ctNode = this.wrap.childNodes[1];
        var cs = this.elNode.childNodes;
        this.indentNode = cs[0];
        this.ecNode = cs[1];
        this.iconNode = cs[2];
        var index = 3;
        if(cb){
            this.checkbox = cs[3];
            Ext.fly(this.checkbox).on('click', this.check.createDelegate(this,[null]));
            index++;
        }
        this.anchor = cs[index];
        this.textNode = cs[index].firstChild;
    },
   
    // private
    check : function(checked){
        var n = this.node;
  var tree = n.getOwnerTree();
  this.checkModel = tree.checkModel || this.checkModel;
  
  if( checked === null ) {
   checked = this.checkbox.checked;
  } else {
   this.checkbox.checked = checked;
  }
  
  n.attributes.checked = checked;
  tree.fireEvent('check', n, checked);
  
  if(this.checkModel == 'single'){
   var checkedNodes = tree.getChecked();
   for(var i=0;i<checkedNodes.length;i++){
    var node = checkedNodes[i];
    if(node.id != n.id){
     node.getUI().checkbox.checked = false;
     node.attributes.checked = false;
     tree.fireEvent('check', node, false);
    }
   }
  } else if(!this.onlyLeafCheckable){
   if(this.checkModel == 'cascade' || this.checkModel == 'parentCascade'){
    var parentNode = n.parentNode;
    if(parentNode !== null) {
     this.parentCheck(parentNode,checked);
    }
   }
   if(this.checkModel == 'cascade' || this.checkModel == 'childCascade'){
    if( !n.expanded && !n.childrenRendered ) {
     n.expand(false,false,this.childCheck);
    }else {
     this.childCheck(n); 
    }
   }
  }
 },
   
    // private
 childCheck : function(node){
  var a = node.attributes;
  if(!a.leaf) {
   var cs = node.childNodes;
   var csui;
   for(var i = 0; i < cs.length; i++) {
    csui = cs[i].getUI();
    if(csui.checkbox.checked ^ a.checked)
     csui.check(a.checked);
   }
  }
 },
 
 // private
 parentCheck : function(node ,checked){
  var checkbox = node.getUI().checkbox;
  if(typeof checkbox == 'undefined')return ;
  if(!(checked ^ checkbox.checked))return;
  if(!checked && this.childHasChecked(node))return;
  checkbox.checked = checked;
  node.attributes.checked = checked;
  node.getOwnerTree().fireEvent('check', node, checked);
  
  var parentNode = node.parentNode;
  if( parentNode !== null){
   this.parentCheck(parentNode,checked);
  }
 },
 
 // private
 childHasChecked : function(node){
  var childNodes = node.childNodes;
  if(childNodes || childNodes.length>0){
   for(var i=0;i<childNodes.length;i++){
    if(childNodes[i].getUI().checkbox.checked)
     return true;
   }
  }
  return false;
 },
 
    toggleCheck : function(value){
     var cb = this.checkbox;
        if(cb){
            var checked = (value === undefined ? !cb.checked : value);
            this.check(checked);
        }
	}
});